The present invention concerns a connector to allow an inflow tube of a blood pump to be securely fastened to the heart.
Clinical application of ventricular assist devices to support patients with end-stage heart disease as a bridge to cardiac transplantation or as an end stage therapeutic modality has become an accepted clinical practice in cardiovascular medicine. It is estimated that greater than 35,000 persons suffering from end stage cardiac failure are candidates for cardiac support therapy.
Currently, several ventricular assist devices are used clinically, and several more are undergoing development. In most of these devices, blood enters the device via an inflow tube, which is placed within the ventricular cavity. A sewing ring is usually attached to the ventricular apex of the heart and an inflow tube of a blood pump is inserted through the sewing ring and into the ventricle. The blood pump is then secured to the sewing ring by placing a ligature, or tie, around the inflow tube of the pump and the sewing ring and tightening them together. A nylon band can also be placed around the sewing ring collar and tightened down on the inflow tube. By this method an adequate seal can be made and the pump and inflow tube are held in place. However, this method makes it very difficult to change the orientation of the inflow tube, or if necessary, to remove the inflow tube from the ventricle. Additionally, placing and tightening a nylon band and ligatures around the inflow tube can be difficult and comprises extra steps in the implant process.
Presently, there are some connection devices that use multiple screw type connectors, for ventricular assist devices on the outflow side. On the inflow side, the ligature tie method and devices have generally been used as well as some screw type connection devices. With total artificial hearts, various screw type devices, twist-lock devices, and snap on connectors have been used. All of these connectors have the disadvantage of requiring the use of two hands to install. Further, in the area where these devices must be installed, space is very limited and installation of these devices is difficult.
It is therefore an object of the present invention to provide an easy to use quick connect and disconnect device for connecting a tube to a patient""s heart.
It is another object of the present invention to provide a device that provides a seal in the connection of a tube to a heart and allows for easy rotation of the orientation of a tube of a blood pump, after insertion into a heart.
It is a further object of the present invention to provide an adapter sleeve for attachment to a tube of a blood pump in order to accommodate different sized hearts and pumps.
Other objects and advantages of the present invention will become apparent as the description proceeds.
In accordance with the present invention, a connector for connecting an inflow tube of a ventricular assist device to a heart is provided. The connector comprises a first member for attachment to a heart, a gripping member adapted for receiving the inflow tube, the gripping member being adapted for coupling to the first member. A second member is provided, for enabling hand manipulation of the gripping member, to permit an operator to open the gripping member to enable the inflow tube to be received and gripped by the gripping member.
In the illustrative embodiment, the connector of the present invention is designed to be attached to the ventricular apex of a heart. The first member is a sewing ring adapted to be sewed to the heart. The gripping member comprises a cylindrical ring defining two openings in its wall, diametrically opposed to each other, through which gripping rods are disposed. A gripping head, which comprises a titanium metal pad having grip teeth to assist in holding, is coupled to each gripping rod such that the gripping head is disposed within the area defined by the cylindrical ring.
In the illustrative embodiment the second member is a spring ring, composed of titanium, which surrounds the cylindrical ring in a concentric ring relationship. The gripping rods are attached to the spring ring and the gripping heads are, as a result, biased towards each other and the center of the area defined by the cylindrical ring, when the spring ring is in a first, at rest, position. The gripping rods, which are also made of titanium, are attached to the spring ring by welding. When the spring ring is squeezed, at points away from the points of connection of the gripping pins, the deformation of the spring ring causes the gripping pins to be pulled back allowing an inflow tube of a ventricular assist device to be inserted into the connector. Releasing the spring ring causes the gripping pins to move towards their first position until they engage the inflow tube. Further squeezing of the spring ring causes the release of the gripping pins from the inflow tube to allow the inflow tube to be adjusted, manipulated or withdrawn.
In the illustrative embodiment, an O-ring seal is provided for insertion into a groove in the cylindrical ring. The O-ring may be installed in the cylindrical ring so as to form a leak proof seal between the inflow tube and the ventricle apex connector. In the illustrative embodiment, the inflow tube of the ventricular assist device is provided with a textured surface to facilitate the gripping of the tube by the gripping members.
In an alternate embodiment a ventricular assist device for a heart is provided which comprises a pump portion, an inflow tube protruding from the pump portion and an adapter sleeve of a first predetermined length attached to the inflow tube forming an extended inflow tube having a total length greater than the first predetermined length. The adapter sleeve may include a first end having a coupling in order to attach the adapter sleeve to a ventricular apex of a heart. The adapter sleeve may have the coupling attached to a sewing ring that is attached to the ventricular apex. The adapter sleeve may be formed of a smooth cylinder of titanium. The adapter sleeve may include cylindrical grooves forming perforations on the surface of the sleeve wherein the sleeve may be separated along said grooves. The adapter sleeve may be formed of ceramic. The adapter sleeve may include a gripping member for attaching the extended inflow tube to the ventricular apex.
In a further alternate embodiment an inflow tube includes a bent end, an extendable end and/or a rotatable end. The inflow tube may include an inner sleeve that is rotatably and slidingly mounted therein in order to allow for the positioning of the tube in variable locations in the assisted organ.
A more detailed explanation of the invention is provided in the following description and claims and is illustrated in the accompanying drawings.